Charles e



(No Model.)

MC. E. SCRIBNBR. VSPRING JACK POR TELEPHONE SWTGHBOARDS.

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Unire STATES ATENT Fries.

CHARLES E. SCRIBNER, OF CIIICAGO, ILLINOIS, ASSIGNOR TO TI'IE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

SPRING-JACK FOR TELEPHONE-SWITCHBOARDS.

SPECIFICATION forming part of Letters Patent No. 552,725, dated January 7, 1896.

Application filed July 30, 1892. Serial No. 441,765. (No model.)

To @ZZ whom it may concern: portions of the jack are mounted in suitable Be it known that I, CHARLES E. SCRIBNER, openings and grooves in a solid block or plate a citizen of the United States, residing at Chiof insulating material, said plate being prefcago, in the county of Cook and State of Illierably molded with the necessary openings 55 5 nois, have invented a certain new and useful and channels. The metallic portions of the Improvement in Spring-Jacks for Telephonespring-j ack comprise simply a metallic tube Switchboards,(Case No. 313,) of which the folor thimble adapted to make connection with lowing is a full, clear, concise, and exact dethe sleeve of a plug, a flexible line-spring scription, reference being had tothe accompacarrying a pyramidal or conical formed con- 6o 1o nying drawings, forming a part of this speeitact on its upper surface, and a conductingiication. strap above the said spring havinga contact- My invention relates to spring-jacks for telsurface upon which the contact-point carried ephone-switchboards. Its object is to provide by the line-spring may bear. This line-sprin g a spring-jack of simple and durable construcand its contact-strap are mounted in a groove 6 5 15 tion, and so constituted as to avoid the accumilled or formed in the under surface of the mulation and incrustation of dust between insulating supporting-plate, and are secured the contact-surfaces of the spring-jack. in place therein by a screw passing through I-Ieretofore it has been customary to mount both into the supporting-plate, and insulated a number of spring-jacks-usuallytwentyfrom the contact-strap by suitable bushings. 7o 2o upon the single supporting-plate of insulating This groove is so curved and formed that the material. This supporting-plate has comcontact-strap and the contact-point upon the monly been made in two or more parts, the flexible spring are protected or shielded from different metallic portions of the different dust. The line-spring and `contact being on spring-jacks beingsecured bysuitable screws, the under side of the supporting-plate, and 75 2 5 bolts and pins in their proper positions upon thus protected, whatever dust enters the the different portions of the supporting-plate. spring-jack will either fall through the open- The spring-jack has comprised a metallic ings in the under side of the plate containing tubular thi1nble, a flexible metallic con the line-spring or will accumulate upon the tact adapted to make connection with a suitupper surface of the line-spring around the 8o 3o ably-formed plug when the latter is inserted pyramidal contact-point. None can by any into the springjack, and a contact-stud promeans become incrusted upon the contactj ecting through the insulating-plate beneath surface of the strap. The parts of a suitable the flexible spring and so disposed that the number of my spring-jacks may be mounted spring rests upon it and makes electrical conupon a single supporting-plate, as heretofore. 8 5 3 5 nection with it when in Vits normal position, I am thus enabled to construct a spring-jack the spring being separated from the stud having few and simple parts,and so consti when the plug is inserted. In these springtuted as to entirely avoid danger arising from jacks the contact-surfaces between the linethe accumulation of dust upon the spring spring and the stud were broad, and whether jack. 9o 4o the line-spring were placed on the under or My invention is illustrated in the accom-` upper side of the plate dust accumulated panying drawings. Therein I have shown upon one or the other contact-surface, formvarious views of a strip containing twenty ing an incrustation thereon and thus eventuspring-jacks organized in accordance with my ally preventing electrical connection. invention.

4 5 My invention is designed to avoid the com- Referring to the drawings, Figure l therein plicated structure which has hitherto been is a front elevation of a strip of springjacks. necessary in the spring-jacks, and at the Fig. 2 is a view of the same from beneath. same time to so constitute and arrange the Fig. 3 is a rear elevation of the strip. Fig. 4c contact-surfaces as to make the accumulation is an end elevation thereof. Fig. 5 is a cenroo 5o of dust between them impossible. tral longitudinal sectional view of a single In my improved springjack the metallic spring-j ack, being a transverse section of the strip of spring-jacks on the centerline of a single jack. Fig. 6 is a section of a single spring-jack taken on the line (i (5 of Figs. 1 and 5, disclosing the means whereby connection is made to the thimble or metallic ring of the spring-jack from the rear of the strip.

I will now describe in detail my invention as depicted in the drawings, indicating parts therein by letters of reference, like parts being designated by similar letters.

Referring to Fig. 5, the spring-jack will be seen to consist essentially of a metallic tubin lar thimble a enlarged at its outer extremity, having a shoulder formed on its outer surface; a flexible metallic spring Z), having its length extending parallel with the axis of the tubular thimble, and one extremity being presented in front of the opening thereof; a conducting-strap c above the spring l), and a plate CZ of insulating material whereon the parts are mounted. The spring b is curved at its forward extremity, so as to more readily ride upon the end of an inserted plu rlhe spring carries, also, the contact-point b rigidly secured to it. The spring I) and the strap c are provided with narrow extensions h2 and c', respectively, at the rear of the strip of spring-jacks, whereby to attach the line-terminals to the springs. The spring b and the strap c are mounted in a groove df, milled or otherwise formed in the under surface of the plate (Z of insulating material, being secured therein by a screw c passing through both into the plate d. The groove d is formed as shown in Fig. 5, the upper wall of the groove being curved to extend below the extremity of the strap c and to form a shield before the contact-point. The crowding of dust forward under the contact-point by the repeated insertion of the plug is thus largely prevented. The strap c is insulated from the screw by a suitable bushing e/ of insulating material and is separated from the spring b by a washer c2, also of insulating material. The tube or thimble a is inserted into the perforation d2 extending from the front of the plate (l to a suitable depth and meeting the milled groove within which the parts b and c are mounted. The thimble a is provided with an oblique metallic extension a', which, when the thimble is placed in position, is inserted through an oblique duct d3 and thence through a transverse saw-cut d4 in the surface of the insulating-plate d. The extension a is of such length that when the thimble is placed in the strip it extends to the rear of the jack to an equal distance with the soldering extensions of the spring b and the strap c. Connection may thus be made to the thimble a by soldering the line-wires to the extension a at the rear of the jack. The thimble a is secured in the perforation (Z2 by a pin a2 extending through the material of the plate into the thimble.

In the construction of the strips containing a large number of spring-jacks, the plate Z is formed or molded with the requisite number of grooves df, perforations d2, the oblique ducts d3 and transverse saw-cuts (Z4 necessary to accommodate the corresponding parts of the spring-jacks. The metallic portions of the spring-jacks are then mounted thereon in the position and manner described.

l do not desire to claim in this application the combinations of the oblique extension a/ with the thimble u, and the oblique duct d3 and the saw-cut d4 to lead said extension to the rear of the strip of springjacks. This device is described and fully claimed in a joint application of lV. R. Patterson and m fself for a patent on Spring-jack switches for telephone switchboards,7 filed January 21, 1892; but

I claim as new and desire to secure by Letters Patent- 1. ln a spring jack, the combination with a supporting plate of insulating material provided with a groove or channel in its under side, of a flat strip c secured to the upper wall of said channel, said wall being provided with a downward projection in front of the end of said strip, a line spring beneath said strip, and a contact anvil mounted upon the upper surface of said line spring and adapted to make contact with the under side of said strip; substantially as described.

2. The combination with a supporting plate CZ of insulating material having perforations cl2 and the grooves d formed therein, of the thimbles d in said perforations, the contact springs b carrying contact points b and the contact straps c therefor mounted in said grooves, and the screws e passing through said springs Z1 and straps c into said plate d to secure them to the same, substantially as described.

In witness whereof l hereunto subscribe my name this 28th day of June, A.4 D. 1892.

CHARLES E. SCRIBNER. lVitnesses:

FRANK R. MCBERTY, WALTER L. SMITH.

IOO 

